Study On The Source Control Of Chemical Fertilizer Non-point Source Pollution In Vegetable Production In Qingdao Dagu River Basin

At present,the domestic fertilization technology is more emphasis on the control of fertilizer application rate on crop growth or fertilizer utilization,but the study of chemical fertilizer non-point source pollutant reduction is less.This paper is to study the source control of non-point source pollution of chemical fertilizers based on the formula fertilization of vegetable production in Dagu River Basin with the goal of agricultural fertilizer non-point source pollution reduction.The main results are as follows:1,The current situation of chemical fertilizer non-point source pollution in the watershed of vegetable field is more serious: 1)The soil acidification and the accumulation of nitrogen and phosphorus were serious,significantly decreased with the increase of soil depth,and the situation of the greenhouse vegetable field was more serious than that of open-air vegetable field.In 2014,each index concentration of surface water in dry season is generally less than the wet period or normal water period,total nitrogen exceed the standard.And the content of nitrate nitrogen in groundwater Wells is generally on the high side,some far beyond the groundwater environmental quality standard of ? class water indicators.2,The small rape simulation experiment of soil column leaching showed that: compared to conventional one-time fertilization,separately fertilization could improve fertilizer use efficiency,increase rapeseed yield,and can significantly reduce the leaching of soil nitrate nitrogen,play a certain effect on the nitrogen pollutant emission.In the case of phosphorus,the accumulated amount of phosphorus in habitual fertilization was greater than that of sub fertilization,and the effect of leaching was not significant.3,Carrot in situ fertilizer utilization and leaching experimen results show that: 1)The fertilizer utilization rate of the formula fertilization was higher than that of the conventional fertilization treatment,the nitrogen use efficiency> the potassium fertilizer utilization rate> the phosphorus fertilizer utilization rate.The yield of formula fertilization treatment were higher than that of conventional fertilization treatment,the proportion of carrot were lower than the conventional fertilization treatment;1)the effects of formula fertilization on nitrogen and phosphorus emission reductions is remarkable,soil nitrate nitrogen under different fertilizer treatments have significant residual,and the treatment of conventional fertilization was the highest.The contents of available N,total N,available P and total P decreased with the increase of soil depth,and that of conventional fertilization treatment was the highest,The formula fertilization improved the nutrient absorption and utilization efficiency,and reduced the residue amount of N and P in soil.4,Carrot 2+X total nitrogen control and leaching experiment results show that:1)The carrot yield and carrot specific weight were the highest in 100% nitrogen proportion optimization area;2)The optimum fertilization could significantly improve the quality of carrot,and the 100% optimized N region is higher than that of 70% and 130% in optimized N area.Appropriate nitrogen fertilizer can improve the quality of carrot right,and both the deficiency and excessive amount of nitrogen fertilizer could lower the quality of carrot.On nitrate,optimized fertilization improved the utilization rate of fertilizer and other nutrients,as well as the content of nitrate in carrot.3)In the case of soil nitrate contents,conventional fertilization nitrogen area > 130% optimized nitrogen area > 70% optimized nitrogen area > 100% optimized nitrogen area > nitrogen free area,optimize nitrogen can reduce nitrate nitrogen leaching,of which 100% optimized nitrogen area to reduce the effect of nitrate nitrogen leaching was the best,conventional fertilization treatment leaching is more strong.